// 1.导入redux(不能通过ES6方式导入)
// commonjs一种实现 -> nodejs

const redux = require('redux')

const initState = {
  counter: 0
}

// reducer
function reducer(state = initState, action) {
  switch(action.type) {
    case "INCREMENT":
      return {...state, counter: state.counter + 1}
    case "DECREMENT":
      return {...state, counter: state.counter - 1}
    case "ADD_NUMBER":
      return {...state, counter: state.counter + action.num}
    case "SUB_NUMBER":
      return {...state, counter: state.counter - action.num}
    default:
      break;
  }

}

// store(创建的时候需要传入一个reducer)
const store = redux.createStore(reducer)

// 订阅store的修改
store.subscribe(() => {
  console.log("state发生了改变", store.getState() && store.getState().counter)
  
})



// actions
const action1 = {type: "INCREMENT"}
const action2 = {type: "DECREMENT"}
const action3 = {type: "ADD_NUMBER", num: 5}
const action4 = {type: "SUB_NUMBER", num: 12}


// 派发action
store.dispatch(action1)
store.dispatch(action2)
store.dispatch(action2)
store.dispatch(action3)
store.dispatch(action4)

